On November 16, 1990, the EPA published the final ruling regulating industrial storm water discharges at airports. This ruling implements Section 402 (p) of the Clean Water Act, which requires the EPA to establish regulations under the National Pollutant Discharge Elimination System, a permit program that requires airports to have a storm water discharge permit.
Billings Logan International Airport submitted for a group storm water discharge application on August 26, 1991 as part of the AAAE/ARDF application, and had the Airport's storm water discharge sampled in August 1992. On August 24, 1993, the State of Montana notified all group storm water applicants that they would not adopt this general permit for use in the State and that the Airport would be required to apply for coverage under one of three general permits for storm water discharges by January 1, 1994. Billings Logan International Airport submitted an application and received authorization MTR000304 to Discharge under the "General Discharge Permit for Storm Water Associated with Industrial Activity" general permit category. The Airport is required to renew its General Permit periodically.